Macrolide antibiotics have been used extensively in treating a wide range of bacterial infections. The macrolide antibiotic, 6-O-methylerythromycin A (clarithromycin), is particularly useful in treating common pediatric infections of the middle ear and upper respiratory tract. When macrolide antibiotics are administered to children and other patients who experience difficulty or reluctance in swallowing solid dosage forms (such as tablets or capsules), liquid formulations such as solutions, emulsions, and suspensions are preferred. However, macrolide antibiotic are extremely bitter, and even trace quantities dissolved in liquid dosage form are often perceived as unpalatable. Consequently, it has been sought to mask the taste of such drugs by preparing them as suspensions, in a flavored liquid, of fine particles which are coated or sealed with an agent that prevents the dissolution of the drug until after the particles have been swallowed. In this manner, adequate taste masking has been achieved while maintaining the desired pharmacokinetic properties. The most favorable results to date have been obtained with oral liquid suspensions in which the above particles consist of complexes or absorbates of a macrolide antibiotic and a carbomer, as described in U.S. Pat. No. 4,808,411, issued to Fu Lu et al. on Feb. 28, 1989.
These complexes or absorbates are typically prepared by dissolving the drug in a mixture of acetone and alcohol and adding carbomer, or by mixing a slurry of the drug and carbomer in acetone or an acetone/alcohol mixture. However, utilization of the aforementioned processes on an industrial scale presents a number of problems, including employee safety, emissions of solvent vapors to the atmosphere, and cost. Accordingly, a particular need exists for a process which does not employ alcohol or organic solvents.